Pneumatic chipping hammer



Oct. 19 1926.

- w. F. ZIMMERMANN PNEUMATIC CHIPPING HAMMER Filed March 27, 1925 3 Sheets-Sheet 2 INVENTOR ma 1' amF .21 mmcumann.

HIS ATTNEY Oct. 19 1926. I 1,664,011 I w. F. ZIMMERMANN PNEUMATIC CHI PPING HAMMER Filed March 27, 19 5 3 Sheets-Sheet 3 I]: ll

, c Elf lNVE NTOR v I in la and? Zimmerman):

H l S ATTOgEY distributingvalve, andrend'er the valve more Patented Oct. 19, 1926.

\ UNITED S'TAT-ERS I 1,604,011 PATENT aoFFIcE.

WILLIAM F. ZI MME RMANN, OF WAVERL Y, NEW Y RK, ASSIGNOR T INGEESOLL- RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATIGN OFNEW JERSEY.

PNEUMATIC GHIPPING HAMMER.

Application filed March 27, 1925. "Serial No. 18,656.

This invention relates to pneumatic hammers, but more particularly to high speed pneumatic chipping hammers for steel casting and billet work, especially designed for cleaning and chipping steel castings and for scaling and chipping high carbon and alloy steel billets.

The objects of the invention are in general to enable a high speed hammer to be "constructed'in a simple and rugged manner which insures long life; make the hammer easier to hold in which the high speed enters as an important factor, obtain good bal ance and enable the operator to readily control the force of the blows of the hammer piston.

Further important objects. are to improve upon theconstruction and operation of the sensitive and at the same time more dependhighspeeds.

Additional objects of the invention Wlll hereinafter appear and to all ofthese ends the invention consists ofthe features of construction, combinations of elements and arm companying drawings, illustrating one prebox,

Figure 4 is a similar view of the-rearward; valve box cap and exhaust deflector,

rangement of parts, having the general mode of operation as herelnafter more fully described and claimed, andshownin the acferred form of the invention, in which,

Figure 1' is a sectional elevation of the chipping hammer,

Figure 3 is a simllar vlew of the valve Figure 5 is an enlarged detail longitudinal sectional elevation partly broken away of the valve and valve box assembly,

:Flgltfe 6 isa perspective view of the' exhaust deflector, i

sectional. elevation partly broken" away of the"cylinder and valve ass'embly showing the distributionof the pressurefluid, and

Figure 8 is a view similanto Figure 7 withilthe valve iiranother position.

' Reierrin'gto the drawings the'cylinder or Figure I is a conventional longitudinal of thecylinder. The rearward portion of the cylinder is provided-with an enlarged bore F to receive the valve box G in the form of a hollow block, and also to receive the forward valve box cap H and the'rearward valve box cap J. The valvebox and the two capstogether form a complete valve chestor cage. The-handle K having the handle grip L forms thebaclrhe'ad of the shipping hammer and is suitably secured to the barrel as by means ofthe bolts Y The handle grip contains the throttle valve (not shown) controlled by the latch P for supplying' pressure fluid tot-he machine.

i The pressure fluid actuated distribution valve preferablyof the diflerential type and is located in the valve box G with its plied to' 't-he machine from the supply pasable and uniformin its action especially at F pointlocated rearwardly ofthe valve. This main exhaust is conveniently located in" the rearward valve box cap J and an exhaust defiectorT' isprovlded for th s main exhaust -betweenthe handle and cyllnder.

In accordance with this invention, the supply of pressurefluid to both ends otthe "cylinder is controlled by the valve, and the main free exhaust from the forward end of the cylinderthrough the exhaust passage U I iscontrolled onlybythepiston C, and in Figure 2 "s a detail perspective view in transverse section o f'the forward valvebox trolled'only by'the valve Q. l The exhaust from'the rear end ofthe cylinder through the port W passesthrouglr the valve Q itself to themain exhaust S and is controlled only by the valve.

1 The valve is thrown forward and held in 1' forwardposition bylive fluid pressure act- :ing upon the shoulder of the enlarged head of the valve," and the valve is thrown to rearward position and held in said position ;by live pressure fluid acting against the valve. in a rearward "direction and controlled the neck iD' of the piston "which cooperates with the passage X in the cylinder.

The *differential valve Q is preferably formed with the enlarged head Y- aud t-he neck Z, and the val-ve has an open rearward end a. The: enlargedheadYforms a -rear- Ward shoulder b onfthe valve haxing aiforports and passages indicated for driving the piston forwardly. The rearwardly acting pressure surface of the enlarged head of the valve is subjected to atmospheric pressure when the valve is in its forward position as indicated in Figure 7 through the passageX and the exhaust passage U and the passage V. When live pressure fluid is supplied through the passage T in the cylinder and around the neck D of the piston and through the passage X to the rearward- 1y acting pressuresurface 0 ofthe valve indicated in Figure 8, the valve will be actuated rearwardly and held in rearward position owing to the fact that the area 0 is larger than the area b.

In the operation of the chipping hammer, let it be assumed that the piston is in its rearmost position as indicated in Figure 7 and the valve is in its forward'position in which case live pressure fluid admitted from the passage R in the handle will pass through the rearward valve box cap J and through passages in the valve box around the neck Z of the valve and through a passage in the forward valve box cap and the port 7' to the rearward end of the cylinder 'which will drive the piston forward. At

the time that the edge (Z at the front end of the piston covers the port 6 of the passage X, the edge 7 of the neck '1) will have uncovered the port 9 of the live pressure fluid supply passage T so that pressure fluid will flow around theneck D of the piston and through the port it in the side of the cylinder communicating with the passage X leading to the forward end of the valve so to the differential areas of the valve.

As the valve is thrown rearwardly,live pressure fluid is supplied fromthesupply passage R in the handle around the neck that the valve is then thrown rearwardly due Z of the valve andthrough the supply pasrebound and to live sage V to the frontend'of the cylinder. The piston however, has sufficient momentum to strike its blow upon the chisel shank E and commences its rearward motion before the pressure begins to build up in front of the piston to drive it-rearwardly. This position ofthe parts is shown in Figure -8.- The rearward motion of the piston is due both to as described. v

valve box pressure fluid admitted 1 acting pressure surface a of the valve and the forward end of the valve will thus be open to exhaust through the passage X and the exhaust passage U. At this time the live pressure fluid on the forwardly acting pressure surface 5 of the valve head or shoulder will throw the valve forwardly to the position indicated in Figure 7 and open the auxiliar exhaust for the front 'end of the cylinder through the passage V and over the rearward end of the valve to the main exhaust S; Before this occurs, however, the exhaust from the rearward end of the cylinder as the piston is traveling rearwardly passes out through the port Wand through the ports 7: and 0 in the valve head and through the valve itself to the main exhaust S. Y

The pressure fluid trapped in the rearward end of the cylinder after the valve has rhifted to its forward position but while the piston is moving rearwardly forms a cushion so that the piston is not stopped abruptly and due to its cushion reverses its movement without reversal of the movement of the valve. From this point the cycle is repeated. I i v The construction and arrangement of the valve and the'operation of the piston are highly advantageous in this chipping hammer, since the forward end of the cylinder has amain exhaust through the passage U controlled by the piston, and also has an auxiliary exhaust through the passage V controlled by the valve so that ample exhaust ports are provided for the front'end of the cylinder. The exhaust fromthe rear end of the cylinder is short and direct through the valve itself .to the main exhaust S. By locating the mainexhaust S directly rearward of the valve, the arrangement and location of the ports and passages in the is facilitated. The valve is thrown and held in both directions by live pressure fluid and the action-ispositive and certain sincethe valve is preferably a differential valve. The valve is preferably coaxial with the piston which has the advantage that if the bolts of the handle should become loose and for any reason allow the which might happen if the valve were located transversely in the valve box.- Iclaimi Q J l. A pneumatic hammer comprising acylinder and reciprocating piston, a valve chest located atthe rearward portion of thecylinder, a hollow pressure fluid controlled valve in said valve chest cont-rolling the'supply of pressure fluid to both ends of the cylinder, an exhaust port in said valve chest rearward of the valve communicating with the forward end of the cylinder and controlled only by the piston, an auxiliary exhaust from the forward end of the cylinder controlled only by the valve and passing over one end of the valve to said exhaust port in the valve chest, a main exhaustfrom the rearward end of the cylinder controlled only by the valve for exhausting through the in terior of the valve, and thence direct to said exhaust port in the valve chest, means for actuatingand holding the valve forwardly by live pressure fluid, and means controlled by the piston for actuating and holding the valve rearwardly by live pressure fluid.

2. A pneumatic hammer comprising a cylinder, a reciprocating piston having a neck, a valve box at the rearward end of the cylinder, front and rear caps for said box, a hollow cylindrical valve in said box having its axis extending longitudinally of the cylinder, and formed with a forward enlarged 25 head having a shoulder forming a forwardly acting pressure surface and a neck intermediate the said head and. the smaller open rearward end of the valve, passages controlled by the valve neck for supplying pressure fluid to both ends of the cylinder, a main exhaust rearwardly of the valve, a main free exhaust passage for the front end of the cylinder controlled only by the forward end of the piston and an auxiliary exhaust for said forward end of the cylinder controlled only by the rearward end of the valve and passing over said rearward valve end, exhaust means for the rearward end of the cylinder controlled by the valve and including means for exhausting through the interior of the valve, means for actuating holding the valve forwardly by the pressure of live fluid on the shoulder of the valve head, and a passage controlled by the piston neck for supplying live pressure fluid to the forward surface of the valve head for actuating the valve rearwardly.

In'testimony whereof I have signed this specification.

WILLIAM F. ZIMMERMANN. 

